CLAIMS 1. A DC-feeding-voltage calculating apparatus connected to a plurality of substations that supply electric power to a feeder in a DC electrified section of an electric railroad, the DC-feeding-voltage calculating apparatus calculating a substation voltage applied to the feeder,
the DC-feeding-voltage calculating apparatus comprising:
a model-information storing unit to store model information, the model information including train model information, feeding network model information, and substation model information, the train model information including information for controlling a regenerative power reducing amount in a train existing in the DC electrified section, the feeding network model information including position information on the substation, the substation model information including control information on the substation voltage;
a train-operation-information estimating unit to estimate second train information on the basis of the model information, first train information, a voltage value, and current values of feeders by train direction, the voltage value and the current values being measured in the substation, the first train information being information on a train equipped with a wireless communication apparatus, the second train information being information on a train existing in the DC electrified section and not equipped with a wireless communication apparatus, the train-operation-information estimating unit outputting train operation information including the first train information and the second train information; and
a substation-voltage-setting-value calculating unit to calculate, on the basis of the model information and the

train operation information, a substation voltage setting value for controlling the substation voltage such that regenerative power is increased in a regenerative car existing in the DC electrified section, the substation-voltage-setting-value calculating unit outputting the substation voltage setting value to the substations.
2. The DC-feeding-voltage calculating apparatus according
to claim 1, wherein
the first train information includes information concerning an on-rail position of, a voltage value of a pantograph point voltage of, a current value of an electric current supplied from an overhead line to, power-running power of, regenerative power of, and regeneratable power of, a first train, the first train being equipped with a wireless communication apparatus, the first train measuring the on-rail position, the voltage value of the pantograph point voltage, and the current value supplied from the overhead line, the power-running power, and the regenerative power and estimating the regeneratable power, and
the second train information includes information concerning an on-rail position of, power-running power of, regenerative power of, and regeneratable power of, a second train not equipped with a wireless communication apparatus.
3. The DC-feeding-voltage calculating apparatus according
to claim 1, wherein
the first train information includes information concerning an on-rail position of, a voltage value of a pantograph point voltage of, a current value of an electric current supplied from an overhead line to, power-running power of, and regenerative power of, a first train equipped

with a wireless communication apparatus, the first train measuring the on-rail position, the voltage value of the pantograph point voltage, the current value of the electric current supplied from the overhead line, the power-running power, and the regenerative power,
the second train information includes information concerning an on-rail position of, power-running power of, regenerative power of, and regeneratable power of, a second train not equipped with a wireless communication apparatus, and
the train-operation-information estimating unit estimates, on the basis of the voltage value and the current value included in the first train information, regeneratable power of the first train, includes information concerning the estimated regeneratable power of the first train in the train operation information and outputs the information concerning the estimated regeneratable power.
4. The DC-feeding-voltage calculating apparatus according to claim 2 or 3, wherein the train-operation-information estimating unit
estimates presence or absence of the second train on the basis of voltage values measured in the substations and current values of feeders by train direction, position information on the substation, the on-rail position of the first train, the voltage value of the pantograph point voltage of the first train, and the current value of the electric current supplied from the overhead line to the first train, the current values of the feeders being measured in the substations, the on-rail position of the first train, the voltage value of the pantograph point voltage and the current value supplied from the overhead

line being included in the first train information, includes information concerning the presence or
absence of the second train in the train operation
information, and
outputs the information concerning the presence or
absence of the second train.
5. The DC-feeding-voltage calculating apparatus according to claim 4, wherein, when the DC electrified section is divided into a plurality of subsections by positions of the substations and an on-rail position of the first train, the train-operation-information estimating unit estimates presence or absence of the second train in each of the subsections and estimates the second train information in a section where the second train is estimated to exist.
6. The DC-feeding-voltage calculating apparatus according to claim 5, wherein, when the train-operation-information estimating unit estimates that the second train exists in plural ones of the subsections, the train-operation-information estimating unit regards, as one section, subsections including all subsections where the second train is estimated to exist and estimates the second train information in the subsections regarded as one section.
7. A DC-feeding-voltage calculating apparatus connected to a plurality of substations that supply electric power to a feeder in a DC electrified section of an electric railroad, the DC-feeding-voltage calculating apparatus calculating a substation voltage applied to the feeder,
the DC-feeding-voltage calculating apparatus comprising:
a model-information storing unit to store model

information, the model information including train model information, feeding network model information, and substation model information, the train mode information including information for controlling a regenerative power reducing amount in a train existing in the DC electrified section, the feeding network model information including position information on the substation, the substation model information including control information on the substation voltage;
a train-operation-information estimating unit to estimate second train information on the basis of the model information, first train information, a voltage value, and current values of feeders by train direction, the first train information being information on a train equipped with a wireless communication apparatus, the voltage value and the current values of the feeders being measured in the substation, the second train information being information on a train existing in the DC electrified section and not equipped with a wireless communication apparatus, the train-operation-information estimating unit outputting train operation information including the second train information; and
a substation-voltage-setting-value calculating unit to calculate, on the basis of the model information, the first train information and the train operation information, a substation voltage setting value for controlling the substation voltage such that regenerative power is increased in a regenerative car existing in the DC electrified section, the substation-voltage-setting-value calculating unit outputting the substation voltage setting value to the substations.
8. A DC-feeding-voltage calculating apparatus connected

to a substation that supplies electric power to a feeder in a DC electrified section of an electric railroad and a voltage sensor that measures a voltage value of the feeder, the DC-feeding-voltage calculating apparatus calculating a substation voltage applied to the feeder,
the DC-feeding-voltage calculating apparatus comprising:
a model-information storing unit to store model information, the model information including train model information, feeding network model information, and substation model information, the train model information including information for controlling a regenerative power reducing amount in a train existing in the DC electrified section, the feeding network model information including position information on the substation and the voltage sensor, the substation model information including control information on the substation voltage;
a train-operation-information estimating unit to estimate second train information on the basis of the model information, a voltage value measured in the substation, current values of feeders by train direction, the voltage value measured by the voltage sensor, and first train information on a train equipped with a wireless communication apparatus, the current values of the feeders being measured in the substation, the second train information is information on a train existing in the DC electrified section and not equipped with a wireless communication apparatus, the train-operation-information estimating unit outputting train operation information including the first train information and second train information; and
a substation-voltage-setting-value calculating unit to calculate, on the basis of the model information and the

train operation information, a substation voltage setting value for controlling the substation voltage such that regenerative power is increased in a regenerative car existing in the DC electrified section, the substation-voltage-setting-value calculating unit outputting the substation voltage setting value to the substations.
9. A DC-feeding-voltage control system that controls a substation voltage applied to a feeder in a DC electrified section of an electric railroad,
the DC-feeding-voltage control system comprising:
a substation including a voltage sensor and current sensors set on feeders by train direction;
a train equipped with a wireless communication apparatus; and
a DC-feeding-voltage calculating apparatus, wherein on the basis of: information concerning a voltage value measured in the substation and current values of the feeders by train direction, the current values of the feeders being measured in the substation; information concerning an on-rail position, a voltage value of a pantograph point voltage, a current value of an electric current supplied from an overhead line, the on-rail position, the voltage value of the pantograph point voltage and the current value of the electric current supplied from the overhead line being measured in the train; and model information including position information on the substation, the DC-feeding-voltage calculating apparatus calculates a substation voltage setting value for controlling the substation voltage such that regenerative power is increased in a regenerative car existing in the DC electrified section, the DC-feeding-voltage calculating apparatus outputting the substation voltage setting value

to plural substations that supply electric power to the feeders.
10. A DC-feeding-voltage calculating method applied to an apparatus that calculates a substation voltage applied to a feeder line in a DC electrified section of an electric railroad,
the DC-feeding-voltage calculating method comprising:
an information acquiring step for acquiring: information concerning voltage values and current values of feeders by train direction, the voltage values and the current values being measured in a plurality of substations; first train information on a train equipped with a wireless communication apparatus; and model information including position information on the substations;
a train-operation-information estimating step for estimating, on the basis of the information acquired in the information acquiring step, second train information on a train existing in the DC electrified section and not equipped with a wireless communication apparatus;
a substation-voltage-setting-value calculating step for calculating, on the basis of the model information, the first train information and the second train information estimated in the train-operation-information estimating step, a substation voltage setting value for controlling the substation voltage such that regenerative power is increased in a regenerative car existing in the DC electrified section; and
a substation-voltage-setting-value output step for outputting, to the substations, the substation voltage setting value calculated in the substation-voltage-setting-value calculating step.